PARP1 and infection: In experiments of PARP1 gain of function, infection with adenovirus encoding human PARP1 gene (Ad-PARP1) versus empty vector (Ad-Null) suppressed contractile gene but increased proliferative and migratory gene expression, and increased neointima/media ratio of balloon-injured arteries (day 10) (Fig. 2c, d), indicating that gain of PARP1 promoted the VSMC phenotype switch.